U.S. patent application number 13/918926 was filed with the patent office on 2014-12-18 for coatings for biological fluid filters.
The applicant listed for this patent is Fenwal, Inc.. Invention is credited to Jo Anne Alfaro, Yoshikazu Mizobuchi.
Application Number | 20140367324 13/918926 |
Document ID | / |
Family ID | 49752962 |
Filed Date | 2014-12-18 |
United States Patent
Application |
20140367324 |
Kind Code |
A1 |
Mizobuchi; Yoshikazu ; et
al. |
December 18, 2014 |
COATINGS FOR BIOLOGICAL FLUID FILTERS
Abstract
Filter media, filter devices and methods of making filter media
are disclosed. The filter media includes a coating on at least a
portion of said outer surface. The coating may be polymeric
composition having a molecular chain that includes segments of
non-polar groups and segments of at least one of polar groups or
segments of ionic groups.
Inventors: |
Mizobuchi; Yoshikazu;
(Mundelein, IL) ; Alfaro; Jo Anne; (Arlington
Heights, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Fenwal, Inc. |
Lake Zurich |
IL |
US |
|
|
Family ID: |
49752962 |
Appl. No.: |
13/918926 |
Filed: |
June 15, 2013 |
Current U.S.
Class: |
210/435 ;
210/490; 427/2.31 |
Current CPC
Class: |
B01D 2239/0471 20130101;
B01D 29/0018 20130101; B01D 67/0088 20130101; B01D 2325/02
20130101; A61M 1/0218 20140204; B01D 71/38 20130101; B01D 69/02
20130101; B01D 71/76 20130101; A61M 1/3633 20130101; B01D 2323/12
20130101; B01D 2239/0622 20130101; A61M 1/3496 20130101; A61M
2207/00 20130101; B01D 71/26 20130101; A61M 2202/0439 20130101;
B01D 2239/0478 20130101; B01D 2323/08 20130101; B01D 2323/22
20130101 |
Class at
Publication: |
210/435 ;
210/490; 427/2.31 |
International
Class: |
B01D 29/00 20060101
B01D029/00 |
Claims
1. A filter medium comprising: a) a filter sheet comprising an
outer surface; and b) a coating on at least a portion of said outer
surface, said coating comprising a polymeric composition, said
composition having a molecular chain comprising segments of
non-polar groups and segments of at least one of polar groups or
segments of ionic groups.
2. The filter medium of claim 1 wherein said segments of said
non-polar groups comprise an olefin.
3. The filter medium of claim 1 wherein said segments of said polar
groups comprise vinyl acetate.
4. The filter medium of claim 1 wherein said segments of said ionic
groups comprise acrylic acid.
5. The filter medium of claim 2 wherein said olefin comprises
ethylene.
6. The filter medium of claim 2 wherein said olefin is
hydrophobic.
7. The filter medium of claim 1 wherein said filter sheet comprises
a melt blown, non-woven porous membrane.
8. The filter medium of claim 1 wherein said composition comprises
a polymer of ethylene and vinyl acetate.
9-11. (canceled)
12. The filter medium of claim 1 wherein said composition comprises
a polymer of olefin and acrylic acid.
13-15. (canceled)
16. A filtration device for processing biological fluid, said
device comprising: a) a housing defining an interior chamber and an
inlet port and an outlet port communicating with said chamber; b) a
filter medium within said chamber, said medium comprising a coating
comprising a polymeric composition, said composition having a
molecular chain comprising segments of non-polar groups and
segments of at least one of polar groups or segments of ionic
groups.
17. The filtration device of claim 16 wherein said filter medium
comprises a plurality of sheets wherein at least one of said
plurality of sheets comprises said coating.
18-21. (canceled)
22. A method of making a leukoreduction filter comprising: a)
forming a coating material by dissolving a selected amount of a
polymeric composition comprising segments of a non-polar groups and
at least one of segments of polar groups or segments of ionic
groups in a solvent; and b) contacting at least a portion of a
porous material with said coating.
23. The method of claim 22 wherein said segments of said polar
groups comprise vinyl acetate.
24. The method of claim 22 wherein said solvent comprises a mixture
of hexane and 2-butanone.
25. (canceled)
26. The method of claim 22 wherein the concentration of said
polymeric composition in said solvent is between about 0.1% -2.0%
(w/v).
27. The method of claim 22 wherein the concentration of said
polymeric composition in said solvent is between about 0.14%-1.6%
(w/v).
28. The method of claim 22 wherein said segments of said ionic
groups comprise acrylic acid.
29. The method of claim 28 wherein said solvent comprises a mixture
of hexane and ethanol.
30-34. (canceled)
35. The method of claim 22 further comprising drying said coated
material under one of ambient conditions or elevated
temperature.
36. The method of any one of claims 23-35 comprising drying said
coated material in a convection type oven at 80.degree. C. for
about 30 minutes.
37. (canceled)
Description
FIELD OF THE DISCLOSURE
[0001] The present disclosure is directed to filters for use in the
processing of biological fluids. More particularly, the present
disclosure is directed to filters for removing white blood cells
(leukocytes) from a biological fluid such as blood. Even more
particularly, the present disclosure is directed to leukoreduction
filters including a coating of a polymeric composition that
enhances the wetting capability of the filter and the interaction
of the filter with leukocytes.
BACKGROUND
[0002] Filters are commonly used in the medical field for removing
unwanted components, agents or particulates from a biological
fluid. In the field of blood processing and collection, it is
common to remove leukocytes from the biological fluid or blood
prior to transfusion of the collected blood to a patient.
Leukocytes present in transfused blood can often cause adverse
reactions in the patients receiving the transfusion.
[0003] Filtration requires passage of the biological fluid through
a filter medium that retains the undesired leukocytes and other
components or aggregates while allowing the remaining desirable
components to pass through the medium and be collected for
subsequent transfusion. The filter medium must be sufficiently
wettable such that fluid can flow through the medium. Also, the
filter medium must be sufficiently attracting of leukocytes or
other target cells.
[0004] Leukoreduction and leukofiltration remain a keen area of
interest in the field of blood processing. Accordingly, efforts to
provide filters that are effective in removing as many leukocytes
as possible from a biological fluid in a reduced time and in an
efficient manner are ongoing.
SUMMARY
[0005] In one aspect, the present disclosure is directed to a
filter medium. The filter medium includes a filter sheet having an
outer surface and a coating on at least a portion of said outer
surface. The coating may be polymeric composition having a
molecular chain that includes segments of non-polar groups and
segments of at least one of polar groups or segments of ionic
groups.
[0006] In another aspect, the present disclosure is directed to a
filtration device for processing biological fluid. The device
includes a housing defining an interior chamber and an inlet port
and an outlet port communicating with said chamber. The device also
includes a filter medium within the chamber. The filter medium
includes a filter sheet having an outer surface and a coating on at
least a portion of said outer surface. The coating may be a
polymeric composition having a molecular chain that includes
segments of non-polar groups and segments of at least one of polar
groups or segments of ionic groups.
[0007] In a further aspect, the present disclosure is directed to a
method of making a leukoreduction filter. The method includes
forming a coating material by dissolving a selected amount of a
polymeric composition including segments of a non-polar groups and
at least one of segments of polar groups or segments of ionic
groups in a solvent. The method also includes contacting at least a
portion of a porous material with the coating.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a plan view of a representative leukoreduction
filter;
[0009] FIG. 2 is a cross-sectional side view of a representative
leukoreduction filter; and
[0010] FIG. 3 is an exploded view of a representative
leukoreduction filter including a plurality of filter sheets.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0011] FIG. 1 shows a representative leukoreduction filter that may
be used in accordance with the present disclosure. Filter 10 is
suited for removal of selected components from a biological fluid
such as blood. Filter 10 includes housing 12, which includes outer
walls 14 and 16. Housing 12 and, indeed, filter 10 are preferably
made of a biocompatible material that is also sterilizable using
conventional sterilization techniques commonly used in the assembly
of disposable blood processing sets such as autoclaving, gamma-ray
and/or electron-beam. In one embodiment, housing walls 14, 16 may
be made of a rigid, polymeric material sealed at or near the
periphery thereof. The sealing of walls 14, 16 may be achieved by
adhesive, welding or other forms of sealing attachment.
[0012] In a preferred embodiment, as shown in FIG. 1, housing walls
14 and 16 may be made of a soft, flexible polymeric material.
Examples of suitable polymeric materials for housing walls 14 and
16 include polyvinyl chloride and/or polyolefin. As shown in FIGS.
1 and 2, housing walls 14 and 16 may be joined along their
peripheral edges to form a seal 18. In the embodiment of FIGS. 1
and 2, an additional inner peripheral seal 20 may also be provided,
as described in U.S. Patent Application Publication US
2002/0113003, the contents of which are incorporated herein by
reference. Seals 18 and 20 define a cushioned peripheral
portion.
[0013] Typically, filters of the type described herein may be
included as part of a disposable fluid processing set or kit where,
in its most basic form, the biological fluid is introduced from a
connected or pre-connected source, passed through the filter 10 and
collected in a pre-attached container after it has passed through
the membrane and the undesirable components captured by the filter
medium. Thus, walls 14 and 16 may include inlet and outlet ports 24
and 26, respectively, to allow for introduction and exit of the
fluid. Ports 24 and 26 communicate with an internal chamber 28,
defined by walls 14 and 16. Ports 24 and 26 may be carried by walls
14 and 16, as shown in FIGS. 1 and 2. Ports 24 and 26 may be
separately attached to housing walls 14, 16 or integrally molded
with housing walls 14 and 16. As shown in FIGS. 1 and 2, the inlet
and outlet ports 24 and 26 may be located in a diametrically
opposed relationship on walls 14 and 16. Thus, for example, inlet
port 24 may be positioned closer to the "top" peripheral edge 13 of
filter 10 on wall 14, whereas outlet port 26 may be positioned
closer to the "bottom" peripheral edge 15 of filter 10 and wall 16.
Of course, it will be appreciated that the relative locations of
ports 14 and 16 may be otherwise modified or provided. Ports 24 and
26 define internal flow paths which establish fluid communication
between interior chamber 28 and tubing 27 leading to other
containers or parts of a disposable processing set in which filter
10 is included.
[0014] As shown in FIG. 2, chamber 28 accomodates a filter medium
30. In one embodiment, filter 30 may be provided as a pad that
includes a plurality of pores sized to prevent passage of
leukocytes while allowing other desirable blood components to pass.
In one embodiment, as shown in FIGS. 2 and 3, filter medium 30 may
include a plurality of sheets 31 wherein each sheet 31 includes
pores of a desired diameter and/or size and distribution. In one
embodiment, sheets 31 may be made of melt blown, non-woven fibers.
In accordance with the present disclosure, the fibers may be made
of a suitable polymeric material, such as polyethylene or
polypropylene or other polyolefin. In one embodiment, the
polyolefin may be hydrophobic.
[0015] As shown in FIGS. 2 and 3, filter medium 30 may be made of a
plurality of melt blown, non-woven fiber sheets. In addition,
groups of sheets may provide a filter medium with filter portions
selected to perform particular functions. For example, filter
medium 30 may include a filter portion made up of a plurality of
sheets wherein the filter portion 32 and/or the sheets that make up
portion 32 adjacent or closest to housing wall 14 and inlet port 24
has/have a selected porosity that provides for the removal of
microaggregates and smaller sized particulates. Although FIG. 3
shows only two sheets (for representative purposes only), portion
32 may include more than two sheets and may typically include, but
is not limited to, 1 to 5 sheets to provide a "pre-filter."
[0016] Filter portion 34 may provide the primary or main filter and
may likewise include a plurality of sheets of selected porosity.
Although only 5 sheets are shown (for representative purposes
only), the number of sheets that make up the primary or main filter
may be anywhere from 10 to 30, wherein each sheet has a thickness
of approximately 10 .mu.m to 500 .mu.m.
[0017] Filter portion 36 may provide for the filtration of
additional components and/or serve as a spacer element between
filter portion 34 and housing wall 16. Filter portion 36 which may
also include a plurality of sheets (although only 1 sheet is shown
for representative purposes only) is positioned downstream of
filter portion 34 closer to housing wall 16 and outlet port 26.
Portions 32, 34 and 36 may be brought together and sealed together
to provide a unitary filter pad, i.e., filter medium 30.
Alternatively, some or all of the individual sheets of each of the
filter portions 32, 34 and 36 may be brought together and sealed at
inner seal 20 with housing walls 14 and 16, as shown in FIG. 2.
[0018] The above-described embodiments are representative of an
embodiment of a leukoreduction filter. Other filter structures may
be possible which include more or fewer filter layers or filter
portions.
[0019] In an embodiment, filter medium 30 includes a coating for
enhancing the leukoreduction capability of filter 10 and
interaction of the filter medium 30 with leukocytes. The coating is
preferably a biocompatible polymeric composition that is capable of
withstanding sterilization by autoclaving without degradation. In
one embodiment, the coating includes a polymeric composition
wherein the molecular chain of the composition includes non-polar
groups and one of either polar groups or ionic groups. Preferably,
the polymeric composition is a block co-polymer wherein the
molecular chain includes repeating units of the non-polar group and
one of either polar groups or ionic groups. Preferably, the block
co-polymer is non-randomized.
[0020] In one embodiment, the non-polar groups of the molecular
chain that make up the polymeric composition are olefins. Olefins
that are useful in the coating composition of the present
disclosure are typically polyethylene, polypropylene or
polybutylene. The polar groups in the molecular chain of the
polymeric composition are preferably vinyl groups, such as vinyl
acetate. Thus, in one embodiment, the polymeric composition is a
block co-polymer wherein the molecular chain includes ethylene or
propylene or other polyolefin with groups of vinyl acetate. In one
embodiment, the coating composition is poly (ethylene-co-vinyl
acetate).
[0021] In another embodiment, where the polymer includes olefin
(e.g., ethylene, propylene or butylene) and ionic groups, the ionic
group may be selected from the group of organic acids including,
preferably, acrylic acid. Accordingly, in one embodiment, the
polymeric composition is a block co-polymer wherein the molecular
chain includes groups of polyethylene or polypropylene or other
polyolefin and groups of acrylic acid. In one embodiment, the
coating composition is poly (ethylene-co-acrylic acid).
[0022] In the embodiment where the polymeric composition includes a
block copolymer of olefin and vinyl acetate, vinyl acetate may be
present in an amount of approximately 25%-75% by weight of the
polymeric composition. In a more preferred embodiment, the vinyl
acetate may be present in an amount between approximately 30% and
60% by weight of the polymeric composition, or more preferably,
30%-50% by weight of the polymeric composition. In a further
preferred embodiment, the vinyl acetate may be present in the
polymeric composition in an amount of approximately 40% by weight
of the polymeric composition.
[0023] In an embodiment where the polymeric composition is a block
co-polymer that includes olefin and acrylic acid, the amount of
acrylic acid may be present in an amount of approximately 5%-50% by
weight of the polymeric composition. More preferably, the acrylic
acid may be included in an amount of between 10% and 40% by weight
of the polymeric composition and, more preferably, 10% and 30% by
weight of the polymeric composition. In a further preferred
embodiment, acrylic acid may be present in an amount of
approximately 20% by weight of the polymeric composition.
[0024] Coatings of the type described above may be applied to the
filter pad (i.e., filter medium 30) or one or more, or all of the
individual sheets that make up filter medium 30 by dip coating,
spray coating or other forms of coating. Preferably, the thickness
of the coating applied to the filter pad or filter sheets of filter
medium 30 is such that it does not destruct the porous
characteristics of the filter medium 30, and/or plug the pores in
the filter medium 30.
[0025] Dip coating may be a preferred form of applying the coating
to the filter medium 30 or the individual sheets of filter medium
30. Where the polymeric composition is a block co-polymer that
includes olefin and vinyl acetate, the block co-polymer is
preferably first dissolved in a suitable solvent. Suitable solvents
in accordance with the present disclosure may include C.sub.6 to
C.sub.8 aliphatic hydrocarbons, such as hexane, heptane and octane,
and more particularly, hexane/2-butanone or hexane/ethanol. For
example, where the polymeric composition is a block co-polymer of
ethylene and vinyl acetate segments, the solvent may be
hexane/2-butanone. In one non-limiting example, the ratio of hexane
to 2-butanone may be 1:4. The concentration of the block co-polymer
may be between 0.1 and 2.0 (w/v) and, more preferably, 0.14%-1.6%
(w/v), including, but not limited to, 0.14%, 0.3%, 0.5%, 0.8% and
1.0% (w/v).
[0026] In an embodiment where the block co-polymer includes
ethylene and acrylic acid, i.e., poly (ethylene-co-acrylic acid),
the solvent may preferably be hexane/ethanol. In one specific,
non-limiting example, the ratio of hexane to ethanol in the solvent
may be 1:1. Furthermore, the concentration of the polymer in the
solvent may be between 0.01%-2.0% (w/v) or more preferably between
approximately 0.06%-1.0% (w/v), including, but not limited to,
0.06%, 0.14%, 0.3%, 0.5% and 1.0% (w/v).
Study
[0027] Seven layers of a polymer coated membrane were prepared.
Some of the membranes were coated with a Type A co-polymer which
was poly (ethylene-co-vinyl acetate), while others were coated with
a Type B co-polymer which was poly (ethylene-co-acrylic acid). The
underlying membranes were made of melt blown, non-woven
polypropylene fibers. Different fiber diameters were tested, such
as 0.9, 0.6 and 0.3 microns. Other details of the tested membrane
are set forth in Table 1 below.
TABLE-US-00001 TABLE 1 Type Sample 1 Sample 2 Sample 3 Materials
PP* PP* PP* Fiber Diameter (mode) (.mu.m) 0.9 0.6 0.3 Fiber
Diameter (average) (.mu.m) 1.5 1.1 0.8 Basis Weight (g/m2) 15 15 15
Thickness at 20 gf (mm) 0.16 0.16 0.16 Air Permeability
(cc/cm.sub.2/s) 12 10 5.1 Porosity (%) 90 90 90 Mean Pore Size
(.mu.m) 7 5.6 3.3 *Polypropylene
[0028] The assembled 7-layer membranes were placed in a fixture and
3 ml of whole blood (fresh or held for 24 hours) were passed
through the membrane at a rate of 10 ml per hour. Leukoreduction
and platelet recovery were determined by calculating white blood
cell counts at pre- and post-filtration using a Sysmex KX-21N
Hematology Analyzer and (where the white cell count was at or near
zero) a Becton Dickson FACScan Flow Cytometer. The results are
reported below in Tables 2-5.
TABLE-US-00002 TABLE 2 Leukoreduction (%) of Membranes Coated With
Poly (ethylene-co-vinyl acetate) Poly (ethylene-co-vinyl acetate)
in Mixed Solution of Hexane/2-Butanone (1/4 by Vol.) Polymer
Concentration % Sample 1 Sample 2 Sample 3 Fresh Whole Blood 0.14
0.3 92.64 99.86 0.5 99.94 0.8 93.89 99.94 1 99.93 24 Hr. RT Held
Whole Blood 0.14 99.994 0.3 0.5 99.28 0.8 99.3 1 99.36
TABLE-US-00003 TABLE 3 Platelet Reduction (%) of Membranes Coated
With Poly (ethylene-co-vinyl acetate) Poly (ethylene-co-vinyl
acetate) in Mixed Solution of Hexane/2-Butanone (1/4 by Vol.)
Polymer Concentration % Sample 1 Sample 2 Sample 3 Fresh Whole
Blood 0.14 0.3 100 99.3 0.5 100 0.8 100 100 1 99.1 24 Hr. RT Held
Whole Blood 0.14 0.3 0.5 100 0.8 100 1 99.9
TABLE-US-00004 TABLE 4 Leukoreduction (%) of Membranes Coated With
Poly (ethylene-co-acrylic acid) Poly (ethylene-co-acrylic acid) in
Mixed Solution of Hexane/Ethanol (1/1 by Vol.) Polymer
Concentration % Sample 1 Sample 2 Sample 3 Fresh Whole Blood 0.06
0.14 49.23 99.88 99.997 0.3 78.57 99.92 99.9999 0.5 99.76 1 99.39
24 Hr. RT Held Whole Blood 0.06 99.995 0.14 98.7 99.98 0.3 98.4 0.5
99.83 1 89.89 98.56
TABLE-US-00005 TABLE 5 Platelet Reduction (%) of Membranes Coated
With Poly (ethylene-co-acrylic acid) Poly (ethylene-co-acrylic
acid) in Mixed Solution of Hexane/Ethanol (1/1 by Vol.) Polymer
Concentration % Sample 1 Sample 2 Sample 3 Fresh Whole Blood 0.06
0.14 89.4 99.3 34.1 0.3 93.2 99.5 17.7 0.5 98.7 1 100 24 Hr. RT
Held Whole Blood 0.06 0.14 100 47.4 0.3 99.7 0.5 100 1 95.6
86.1
EXAMPLES
[0029] Without limiting any of the foregoing, the subject matter
described herein may be found in one or more apparatus or devices.
For example in a first aspect of the present subject matter a
filter medium is provided. The filter medium includes a filter
sheet having an outer surface and a coating of a polymeric
composition. The composition has a molecular chain with segments of
non-polar groups and segments of at least one of polar groups or
segments of ionic groups.
[0030] A second aspect of the present subject matter includes the
device in accordance with the above-described first aspect wherein
the segments of the nonpolar groups are olefins.
[0031] A third aspect of the present subject matter includes the
device in accordance with the first or second aspect in which the
segments of the polar groups are vinyl acetate.
[0032] A fourth aspect of the present subject matter includes the
device in accordance with any one of the first or second aspects
described above wherein the ionic group is acrylic acid.
[0033] A fifth aspect of the present subject matter includes the
device in accordance with any one of the first through fourth
aspects described above wherein the olefin is ethylene.
[0034] A sixth aspect of the present subject matter includes the
device in accordance with any one of the first through fifth
aspects described above wherein the olefin is hydrophobic.
[0035] A seventh aspect of the present subject matter includes the
device in accordance with any one of the first through sixth aspect
described above wherein the filter sheet is a melt blown, non-woven
porous membrane.
[0036] An eighth aspect of the present subject matter includes the
device in accordance with any one of the first through third or
fifth through seventh aspects described above wherein the
composition is a polymer of ethylene and vinyl acetate.
[0037] A ninth aspect of the present subject matter includes the
device in accordance with the eighth aspect described above wherein
the vinyl acetate makes up between about 5%-75%, by weight, of the
polymeric composition
[0038] A tenth aspect of the present subject matter includes the
device in accordance with any one of the eighth or ninth aspects
described above wherein the vinyl acetate makes up about 40%, by
weight, of the polymeric composition.
[0039] An eleventh aspect of the present subject matter includes
the device in accordance with any one of the first through tenth
aspects described above including a pad that includes a plurality
of the filter sheets.
[0040] A twelfth aspect of the present subject matter includes the
device in accordance with any one of the first and second, fourth
through seventh or eleventh aspects wherein the composition
includes olefin and acrylic acid.
[0041] A thirteenth aspect of the present subject matter includes
device in accordance with the twelfth aspect described above
wherein the acrylic acid makes up between about 5%-50%, by weight,
of the composition.
[0042] A fourteenth aspect of the present subject matter includes
the device in accordance with any one of the twelfth or thirteenth
aspects wherein the acrylic acid is present in an amount of about
20% of the polymeric composition.
[0043] A fifteenth aspect of the present subject matter includes
the device in accordance with any one of the first through
fourteenth aspects described above wherein the composition is a
random polymer with a molecular chain that includes repeatable
segments of the nonpolar and the at least one of the polar groups
or ionic groups.
[0044] A sixteenth aspect of the present subject matter is a
filtration device for processing biological fluid. The filtration
device includes a housing defining an interior chamber and an inlet
port and an outlet port communicating with the chamber. A filter
media is within the chamber and the medium includes a coating of a
polymeric composition. The polymeric composition has a molecular
chain including segments of nonpolar groups and segments of at
least one of a polar group or a segment of the ionic.
[0045] A seventeenth aspect of the present subject matter includes
the device in accordance with the sixteenth aspect described above
wherein the filter medium includes a plurality of sheets wherein at
least one of the sheets includes the coding.
[0046] An eighteenth aspect of the present subject matter includes
the device in accordance with any one of the sixteenth or
seventeenth aspects described above wherein the segments of the
nonpolar groups are olefins.
[0047] A nineteenth aspect of the present subject matter includes
the device in accordance with any one of the sixteenth through
eighteenth aspects wherein the segments of the polar groups are
vinyl acetate.
[0048] A twentieth aspect of the present subject matter includes
the device in accordance with any one of the sixteenth through
eighteenth aspects wherein the segments of the ionic groups are
acrylic acid.
[0049] A twenty-first aspect of the present subject matter includes
the device in accordance with any one of the sixteenth through
twentieth aspects described above wherein the filter medium is a
melt blown, nonwoven porous membrane.
[0050] A twenty-second aspect of the present subject matter is a
method of making a leukoreduction filter. The method includes
forming a coating material by dissolving a selected amount of a
polymeric composition that includes segments of nonpolar groups and
at least one segment of a polar group or segment of ionic groups in
a solvent. The method further includes contacting at least a
portion of a porous material coating.
[0051] A twenty-third aspect of the present subject matter includes
the method in accordance with twenty-second aspect described above
where in the segments of the polar groups are vinyl acetate.
[0052] A twenty-fourth aspect of the present subject matter
includes the method in accordance with the twenty-second and
twenty-third aspects wherein the solvent comprises a mixture of
hexane and 2-butanone.
[0053] A twenty-fifth aspect of the present subject matter includes
the method in accordance with the twenty-fourth aspect described
above wherein the ratio of the volume of hexane to the volume of
2-butanone is about 1:4.
[0054] A twenty-sixth aspect of the present subject matter includes
the method in accordance with any one of the twenty-second through
twenty-fifth aspects wherein the concentration of the polymeric
composition in the solvent is between about 0.1%-2.0% (w/v).
[0055] A twenty-seventh aspect of the present subject matter
includes the method in accordance with any one of the twenty-second
through twenty sixth aspects wherein the concentration of the
polymeric composition in the solvent is between about 0.14%-1.6%
(w/v).
[0056] A twenty-eight aspect of the present subject matter includes
the method in accordance with the twenty-second aspect described
above wherein the segments of the ionic groups include acrylic
acid.
[0057] A twenty-ninth aspect of the present subject matter includes
the method in accordance with the twenty-eighth aspect described
above wherein the solvent includes a mixture of hexane and
ethanol.
[0058] A thirtieth aspect of the present subject matter includes
the method in accordance with the twenty-ninth aspect described
above wherein the ratio of the volume of hexane to the volume of
ethanol is about 1:1.
[0059] A thirty-first aspect of the present subject matter includes
the method in accordance with any one of the twenty-eight through
thirtieth aspects described above wherein the concentration of the
polymeric composition in the solvent is between about 0.1%-2.0%
space (w/v).
[0060] A thirty second aspect of the present subject matter
includes the method of any one of the twenty-eighth through
thirty-first aspect described above wherein the concentration of
the polymeric composition and the solvent is between about
0.06%-1.0% (w/v).
[0061] A thirty-third aspect of the present subject matter includes
the method in accordance with any one of the twenty second through
thirty-second aspects described above wherein the porous membrane
is a melt blown, nonwoven porous membrane.
[0062] A thirty-fourth aspect of the present subject matter
includes the method in accordance with the thirty-third aspect
described above wherein the melt blown, non-woven porous membrane
is substantially polyolefin.
[0063] A thirty-fifth aspect of the present subject matter includes
the method in accordance with any one of the twenty-second through
thirty-fourth aspects described above including drying the coded
material under ambient conditions or elevated temperature.
[0064] A thirty-sixth aspect of the present subject matter includes
the method in accordance with any one of the twenty-third through
thirty-fifth aspects described above including drying the coded
material in a convection type of an at 80.degree. C. for about 30
minutes.
[0065] A thirty-seventh aspect of the present subject matter
includes the method in accordance with any one of the twenty-second
through thirty-sixth aspects including introducing the coded porous
material between opposed walls of the housing.
[0066] It should be understood that various changes and
modifications to the embodiments described herein will be apparent
to those skilled in the art. Such changes and modifications can be
made without departing from the spirit and scope of the inventions
disclosed herein.
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